Story of the name of Valmiki, the author of Ramayana, is
found in the Avanti Khanda of Padma Purana. As per the story in the Purana,
Valmiki was a robber in his early life. One day he waylaid Saptarishis and tried
to rob them. A dialogue ensued between the Rishis and Valmiki.
The Rishis asked Agnisharma to ask his family members if
they were ready to share the effects of the sins he was committing.
When Valmiki put this question to the members of his family,
they declined to share the fruits of his sins.
Repentant Valmiki came back and reported the matters to
Rishis. They asked to perform Tapa reciting the name of Rama.
For hundreds of years, He sat in the forest chanting the
name of Rama.
He was covered with anthill.
The Rishis then took him out of the anthill and named him as
Valmiki. Valmikam in Sanskrit means anthill.